In school and in everyday life, we sometimes experience rejection by classmates, or we might see someone being excluded from an activity. What do excluded individuals feel? How does the brain process information about being socially excluded? In the past few decades, psychologists and social neuroscientists have investigated the influence of social exclusion on our mind, brain, and behavior. Social exclusion is a complex and ambiguous phenomenon, and therefore, we process information about it dynamically and often cope with it flexibly. In this article, I have described the dynamic effects of social exclusion on our mind, brain, and behavior by developing a model of what happens in the brain and the actions people take upon experiencing social exclusion.

People sometimes perceive a mind in inorganic entities like robots. Psychological research has shown that mind perception correlates with moral judgments and that immoral behaviors (i.e., intentional harm) facilitate mind perception toward otherwise mindless victims. We conducted a vignette experiment (N = 129; Mage = 21.8 ± 6.0 years) concerning human-robot interactions and extended previous research’s results in two ways. First, mind perception toward the robot was facilitated when it received a benevolent behavior, although only when participants took the perspective of an actor. Second, imagining a benevolent interaction led to more positive attitudes toward the robot, and this effect was mediated by mind perception. These results help predict what people’s reactions in future human-robot interactions would be like, and have implications for how to design future social rules about the treatment of robots.

Although human saliva contains the monoamine serotonin, which plays a key role in the modulation of emotional states, the association between salivary serotonin and empathic ability remains unclear. In order to elucidate the associations between salivary serotonin levels, trait empathy, and the sharing effect of emotions (i.e., sharing emotional experiences with others), we performed a vignette-based study. Participants were asked to evaluate their happiness when they experience several hypothetical life events, whereby we manipulated the valence of the imagined event (positive, neutral, or negative), as well as the presence of a friend (absent, positive, or negative). Results indicated that the presence of a happy friend significantly enhanced participants’ happiness. Correlation analysis demonstrated that salivary serotonin levels were negatively correlated with happiness when both the self and friend conditions were positive. Correlation analysis also indicated a negative relationship between salivary serotonin levels and trait empathy (particularly in perspective taking), which was measured by the Interpersonal Reactivity Index. Furthermore, an exploratory multiple regression analysis suggested that mothers’ attention during childhood predicted salivary serotonin levels. Our findings indicate that empathic abilities and the social sharing of happiness decreases as a function of salivary serotonin levels.

Does a major natural disaster change human values and job preferences? The present studies examined whether the experience of a natural disaster experience shifts people’s values and job preferences toward pro-social directions. In Study 1 (cross-temporal analysis), we analysed job application data in nine cities in Japan over 12 years and found that the popularity of pro-social occupations (e.g. firefighter) increased after the Great Hanshin–Awaji Earthquake in 1995, in particular the area hit hardest by the quake. In Study 2 (a large national survey), we found that Japanese respondents who had experienced a major earthquake are more likely to hold a pro-social job than those who never experienced a major earthquake. Together, the current findings suggest that the experience of a major natural disaster shifts human values from the egocentric to the allocentric direction, which in turn could result in a social structure that values pro-social occupations.

People use relatively low-cost signals to maintain close relationships, in which they engage in costlier exchanges of tangible support. Paying attention to a partner allows an individual to communicate his or her interest in the relationship with the partner. Previous studies have revealed that when Person A pays attention to Person B, B’s feeling of intimacy toward A increases. If social attention strengthens the bond between A and B, it is predicted that A’s attention will also increase B’s generous behavior toward A. This study tested this prediction. Participants first engaged in a collaborative task using computers. In the task, the putative partner (a computer program) either paid or did not pay attention to participants (high attention condition vs. low attention condition). In the control condition, the partner could not choose when to pay attention to participants. They then played three rounds of the dictator game with the partner. Confirming the previous finding, perceived intimacy was highest in the high attention condition, in the middle in the control condition, and lowest in the low attention condition. More importantly, participants in the high attention condition decided to give more resources to their partner than those in the low attention condition (but the difference between the high attention condition and the control condition was not significant). In addition, self-reported intimacy was positively correlated with the resource allocated to the partner. The results of this study demonstrated that social attention fosters a partner’s generosity.

People attend to their partners’ pro-relationship behaviors (or commitment signals) which in turn leads to a positive adjustment in perceived strength of interpersonal bonds. This bond-confirming effect is stronger when the commitment signal entails some high cost (e.g., receiving an expensive birthday present), and by contrast, it is weaker when the commitment signal entails a low cost (e.g., receiving a wish of “Happy Birthday”). The present study explored how loneliness moderates sensitivity to commitment signals as well as their absence (i.e., situations where partners fail to signal commitment despite the demands of the situation). Studies with a Japanese student sample (Study 1), a Japanese community sample (Study 2), and an American sample drawn from users of Amazon Mechanical Turk (Study 3) found that loneliness is associated with an insensitivity to commitment signals: The lonelier the participant, the less likely he or she was to positively adjust perceived bond strength in response to a commitment signal. This relative insensitivity was observed irrespective of the costliness of the signal. On the other hand, loneliness did not predict differences in sensitivity to the absence of commitment signals. Implications of these results for the loneliness literature are discussed.

Individuals’ perceptions and their interpersonal communication about a risk event, or risk talk, can play a significant role in the formation of societal responses to the risk event. As they formulate their risk opinions and speak to others, risk information can circulate through their social networks and contribute to the construction of their risk information environment. In the present study, Japanese citizens’ risk perception and risk talk were examined in the context of the Fukushima Daiichi nuclear radiation risk. We hypothesized and found that the risk information environment and risk literacy (i.e., competencies to understand and use risk information) interact to influence their risk perception and risk talk. In particular, risk literacy tends to stabilize people’s risk perceptions and their risk communications. Nevertheless, there were some subtle differences between risk perception and communication, suggesting the importance of further examination of interpersonal risk communication and its role in the societal responses to risk events.

There are two distinct evolutionary mechanisms of altruistic behavior: direct and indirect reciprocity. Humans are motivated not only to reciprocate benefits to benefactors but also to behave altruistically for the maintenance or improvement of their reputation. This study compared the two evolutionary mechanisms of altruistic behavior. Three scenario-based experiments on diverse samples (Japanese undergraduates in Experiment 1, Japanese crowdsourcing workers in Experiment 2, and crowdsourcing workers worldwide in Experiment 3) were conducted by manipulating (1) reciprocity between participants and a colleague (reciprocal or non-reciprocal) and (2) the colleague’s reputation in the workplace (good or bad). When participants received a reciprocal request from their colleague to help, they tended to accept it, even if the colleague had a bad reputation among others. On the other hand, participants were less accepting of a non-reciprocal request from a colleague with a bad reputation than a colleague with a good reputation. These results clearly indicate that humans prioritize the maintenance of direct reciprocal relationships over group-based reputations.

Despite a growing number of studies suggesting that emotion words affect perceptual judgments of emotional stimuli, little is known about how emotion words affect perceptual memory for emotional faces. In Experiments 1 and 2 we tested how emotion words (compared with control words) affected participants’ abilities to select a target emotional face from among distractor faces. Participants were generally more likely to false alarm to distractor emotional faces when primed with an emotion word congruent with the face (compared with a control word). Moreover, participants showed both decreased sensitivity (d′) to discriminate between target and distractor faces, as well as altered response biases (c; more likely to answer “yes”) when primed with an emotion word (compared with a control word). In Experiment 3 we showed that emotion words had more of an effect on perceptual memory judgments when the structural information in the target face was limited, as well as when participants were only able to categorize the face with a partially congruent emotion word. The overall results are consistent with the idea that emotion words affect the encoding of emotional faces in perceptual memory.

Cooperation is fundamental to human societies, and one of the important paths for its emergence and maintenance is reciprocity. In prisoner’s dilemma (PD) experiments, reciprocal strategies are often effective at attaining and maintaining high cooperation. In many public goods (PG) games or n-person PD experiments, however, reciprocal strategies are not successful at engendering cooperation. In the present paper, we attribute this difficulty to a coordination problem against free riding among reciprocators: Because it is difficult for the reciprocators to coordinate their behaviors against free riders, this may lead to inequality among players, which will demotivate them from cooperating in future rounds. We propose a new mechanism, institutionalized reciprocity (IR), which refers to embedding the reciprocal strategy as an institution (i.e., institutionalizing the reciprocal strategy). We experimentally demonstrate that IR can prevent groups of reciprocators from falling into coordination failure and achieve high cooperation in PG games. In conclusion, we argue that a natural extension of the present study will be to investigate the possibility of IR to serve as a collective punishment system.

Punishment of non-cooperators—free riders—can lead to high cooperation in public goods games (PGG). However, second-order free riders, who do not pay punishment costs, reduce the effectiveness of punishment. Here we introduce a “leader support system,” in which one group leader can freely punish group followers using capital pooled through the support of group followers. In our experiment, participants engage in three stages repeatedly: a PGG stage in which followers decide to cooperate for their group; a support stage in which followers decide whether to support the leader; and a punishment stage in which the leader can punish any follower. We compare a support-present condition with a no-support condition, in which there is an external source for the leader’s punishment. The results show that punishment occurs more frequently in the support-present condition than the no-support condition. Within the former, both higher cooperation and higher support for a leader are achieved under linkage-type leaders—who punish both non-cooperators and non-supporters. In addition, linkage-type leaders themselves earn higher profits than other leader types because they withdraw more support. This means that leaders who effectively punish followers could increase their own benefits and the second-order free rider problem would be solved.

Behavioral and neuroscientific studies explore two pathways through which internalized social norms promote prosocial behavior. One pathway involves internal control of impulsive selfishness, and the other involves emotion-based prosocial preferences that are translated into behavior when they evade cognitive control for pursuing self-interest. We measured 443 participants’ overall prosocial behavior in four economic games. Participants’ predispositions [social value orientation (SVO)] were more strongly reflected in their overall game behavior when they made decisions quickly than when they spent a longer time. Prosocially (or selfishly) predisposed participants behaved less prosocially (or less selfishly) when they spent more time in decision making, such that their SVO prosociality yielded limited effects in actual behavior in their slow decisions. The increase (or decrease) in slower decision makers was prominent among consistent prosocials (or proselfs) whose strong preference for prosocial (or proself) goals would make it less likely to experience conflict between prosocial and proself goals. The strong effect of RT on behavior in consistent prosocials (or proselfs) suggests that conflict between prosocial and selfish goals alone is not responsible for slow decisions. Specifically, we found that contemplation of the risk of being exploited by others (social risk aversion) was partly responsible for making consistent prosocials (but not consistent proselfs) spend longer time in decision making and behave less prosocially. Conflict between means rather than between goals (immediate versus strategic pursuit of self-interest) was suggested to be responsible for the time-related increase in consistent proselfs’ prosocial behavior. The findings of this study are generally in favor of the intuitive cooperation model of prosocial behavior.

Many studies have shown that American culture has become more individualistic over time. However, it was unclear whether other cultures, especially East Asian cultures, have also shifted toward greater individualism. Therefore, this article reviewed studies investigating temporal changes in individualism in Japan and their ramifications on psychology and behavior. Japan has experienced rapid and dramatic economic growth and urbanization and has adopted more social systems based on individualistic concepts in various contexts (e.g., workplace, school). Recent studies have suggested that, along with these socioeconomic changes, Japanese culture has become more individualistic over time. Specifically, the divorce rate increased and household size decreased. Moreover, people give more unique names to their children and dogs, and individualistic words such as “individual” and “uniqueness” appear more frequently in newspapers. Furthermore, social values became more individualistic. Yet, it has also been shown that some collectivistic values still remain. As a result, people have difficulty in adapting to this coexistence, which injures interpersonal relationships and well-being. This paper discussed how Japanese culture changed over time and how such changes affected Japanese psychology and behavior.

This study compares Facebook users in Japan, the US, and Taiwan, and users of similar SNSs in China, focusing on their self-disclosure and network characteristics. An online questionnaire survey was conducted in these four countries in 2012/2013. Results indicate that mobile device users use SNS more frequently than desktop/laptop PC users. Results also indicate that cultural differences in SNS use were observed. Across these four countries, the Japanese have the smallest number of Facebook friends; the highest level of homogeneity in their friendship network; the highest proportion of offline friends; are least likely to disclose personally identifiable information; and most frequently read and post messages on Facebook. In contrast, the Chinese are most likely to disclose personal attribute information and Taiwanese are most likely to disclose personal information on SNS. The Japanese also show a positive and significant correlation between network homogeneity, number of Facebook friends, and disclosure of personal information, which suggests that they depend on offline homogeneous relationships more than SNS users in other countries for their Facebook friending process. Structural equation model results indicate that cultural differences in self-disclosure on SNS between Japanese, Taiwanese, and Chinese users are partially explained by relational mobility.

This study describes the Brief Inventory of Social Support Exchange Network (BISSEN) as a standardized brief inventory measuring various aspects of social support. We confirmed the reliability and validity for function and direction of support and standardized the BISSEN. For Sample 1, a stratified random sampling method was used to select 5200 residents in Japan. We conducted mail surveys and responses were retrieved from 2274 participants (collection rate 43.7%). Participants completed a questionnaire packet that included BISSEN, suicidal ideation, depression, support seeking, and Multidimensional Scale of Perceived Social Support (MSPSS). Sample 2 surveys for test-retest reliability were conducted on 23 residents at approximately two-week intervals. Participants were asked about gender, age, and BISSEN. First, we assessed the internal consistency, test-retest reliability, construct, convergent, and concurrent validity. McDonald’s omega (.73–.92) and test-retest correlations (.78–.85) demonstrated adequate internal consistency and test-retest reliability. Depression, support seeking, and MSPSS were significantly correlated with all scores of BISSEN. The non-suicidal ideation group had significantly more support compared to the suicidal ideation group. Therefore, function and direction of support in BISSEN had sufficient reliability and validity. Next, we standardized BISSEN using Z-scores and percentile rank with respect to each 12 norm groups by age and gender.

Despite widespread concern over heated diplomatic debates and growing interest in public diplomacy, it is still incompletely understood what type of message is more effective for gaining support from foreign public, or the international society, in situations where disputing countries compete in diplomatic campaigns. This study, through multiple survey experiments, uncovers the effect of being silent, issuing positive justification, and negative accusation, in interaction with the opponent’s strategy. We demonstrate that negative verbal attacks “work” and undermine the target’s popularity as they do in electoral campaigns. Unlike domestic electoral campaigns, however, negative diplomacy has little “backlash” and persuades people to support the attacker. Consequently, mutual verbal fights make neither party more popular than the other. Nevertheless, this does not discourage disputants from waging verbal fights due to the structure similar to the one-shot prisoner’s dilemma. We also find that positive messages are highly context-dependent—that is, their effects greatly depend on the opponent’s strategy and value proximity between the messenger and the receiver.

This Handbook provides the most comprehensive overview of the role of electoral advertising on television and new forms of advertising in countries from all parts of the world currently available. Thematic chapters address advertising effects, negative ads, the perspective of practitioners and gender role. Country chapters summarize research on issues including political and electoral systems; history of ads; the content of ads; reception and effects of ads; regulation of political advertising on television and the Internet; financing political advertising; and prospects for the future. The Handbook confirms that candidates spend the major part of their campaign budget on television advertising. The US enjoys a special situation with almost no restrictions on electoral advertising whereas other countries have regulation for the time, amount and sometimes even the content of electoral advertising or they do not allow television advertising at all. The role that television advertising plays in elections is dependent on the political, the electoral and the media context and can generally be regarded as a reflection of the political culture of a country. The Internet is relatively unregulated and is the channel of the future for political advertising in many countries.

Quake-induced accident of Fukushima nuclear power plant in 2011 triggered heated argument about the country’s energy policy in Japan. Although many people recognized the risk of nuclear energy use, they did not necessarily support the option of abandoning the technology for the near future. This paper focuses on how people perceive risks associated with and without nuclear power generation and how perceived risks affect their opinion. We conducted questionnaire survey targeting 18–20 year old university students, the stakeholders in the future. The survey was implemented in 2013–2014 when none of Japan’s nuclear power plants was in active use. Three quarters of the respondents answered that a future with nuclear power generation was more realistic than without it. The aspects dividing the two groups, i.e., respondents who expect a future with or without nuclear energy use were their evaluations of three themes: (1) the feasibility of renewable energy sources, (2) the impacts in the safety of developing nations’ nuclear power generation, and (3) the difficulty in gaining the acceptance of residents near the power plants. Meanwhile, both groups above were similarly positive about technological innovation, and were similarly and strongly negative about developing safety management.

Recent research on human behavior has often collected empirical data from the online labor market, through a process known as crowdsourcing. As well as the United States and the major European countries, there are several crowdsourcing services in Japan. For research purpose, Amazon’s Mechanical Turk (MTurk) is the widely used platform among those services. Previous validation studies have shown many commonalities between MTurk workers and participants from traditional samples based on not only personality but also performance on reasoning tasks. The present study aims to extend these findings to non-MTurk (i.e., Japanese) crowdsourcing samples in which workers have different ethnic backgrounds from those of MTurk. We conducted three surveys (N = 426, 453, 167, respectively) designed to compare Japanese crowdsourcing workers and university students in terms of their demographics, personality traits, reasoning skills, and attention to instructions. The results generally align with previous studies and suggest that non-MTurk participants are also eligible for behavioral research. Furthermore, small screen devices are found to impair participants’ attention to instructions. Several recommendations concerning this sample are presented.

Recent studies have empirically validated the data obtained from Amazon’s Mechanical Turk. Amazon’s Mechanical Turk workers behaved similarly not only in simple surveys but also in tasks used in cognitive behavioral experiments that employ multiple trials and require continuous attention to the task. The present study aimed to extend these findings to data from Japanese crowdsourcing pool in which participants have different ethnic backgrounds from Amazon’s Mechanical Turk workers. In five cognitive experiments, such as the Stroop and Flanker experiments, the reaction times and error rates of Japanese crowdsourcing workers and those of university students were compared and contrasted. The results were consistent with those of previous studies, although the students responded more quickly and poorly than the workers. These findings suggested that the Japanese crowdsourcing sample is another eligible participant pool in behavioral research; however, further investigations are needed to address issues of qualitative differences between student and worker samples.

One of the most well-known models to characterize cooperation among unrelated individuals is Social dilemma (SD). However there is no consensus about how to solve the SD by itself. Since SDs are often embedded in other social interactions, including indirect reciprocity games (IR), human can coordinate their behaviors across multiple games. Such coordination is called ‘linkage’. Recently linkage has been considered as a promising solution to resolve SDs, since excluding SD defectors (i.e. those who defected in SD) from indirectly reciprocal relationships functions as a costless sanction. A previous study performed mathematical modeling and revealed that a linkage strategy, which cooperates in SD and engages in the Standing strategy in IR based on the recipients’ behaviors in both SD and IR, was an ESS against a non-linkage strategy which defects in SD and engages in the Standing strategy in IR based on recipients’ behaviors only in IR (Panchanathan and Boyd, 2004). In order to investigate the robustness of the linkage strategy, we devised a non-linkage strategy, which cooperates in SD but does not link two games. First, we conducted a mathematical analysis and demonstrated that the linkage strategy was not an ESS against cooperating non-linkage strategy. Second, we conducted a series of agent-based computer simulations to examine how the strategies perform in situations in which various types of errors can occur. Our results showed that the linkage strategy was an ESS only when there are implementation errors in SD. However, the equilibrium of the linkage strategy was unstable when there are perception errors. Since we know that humans are not free from perception errors in their social life, future studies will need to show how perception errors can be overcome in order to provide support for the conclusion that linkage is a plausible solution to SDs.

People generally tend to discount future outcomes in favor of smaller but immediate gains (i.e., delay discounting). This study examines the hypothesis that culture and social status moderate this tendency, as well as the alternative hypothesis that social status and culture influence delay discounting independently of each other. American and Japanese adults were asked to choose receiving hypothetical monetary rewards either immediately or receiving rewards of different amounts with a delay of 1 year. The results replicated previous findings and supported the alternative hypothesis. Delay discounting was lower when subjective socioeconomic status (i.e., an individual’s perception of her or his social rank) was higher. Also, the Japanese were less likely to discount future rewards than the Americans. However, there was no interaction between social status and culture in influencing the rates of delay discounting.

This article reviews how behaviors and psychological tendencies in close relationships differ between cultures, and proposes a socioecological framework to understand those differences. Our review of the literature finds that paradoxically, people in individualistic cultures are more actively engaged in close relationships (e.g., higher levels of social support, self-disclosure, intimacy, and love) than those in collectivistic cultures. From an adaptationist perspective, we argue that one reason for these differences is higher levels of relational mobility in individualistic cultures. In societies with high relational mobility, where relationships are relatively more fragile, more active engagement in close relationships helps individuals to impress potential, and retain current, partners. We emphasize the importance of examining socioecologies to better understand close relationships.

Previous research on relationship quality concepts suggests they are not as distinct as expected. What aspects are similar and distinct across these concepts? Using a prototype approach, this research identified the commonalities and uniqueness of 7 relationship quality concepts: commitment, intimacy, love, passion, satisfaction, trust, and relationship quality. The results indicated that (a) 4 features were shared across all 7 concepts, and some were exclusive to each concept, and (b) shared features were rated as more important for romantic relationship functioning than unique features both explicitly and implicitly. This research provides a framework to understand overarching and distinct aspects of relationship quality concepts and how this is reflected in people’s evaluation of what is important in romantic relationships.

Previous studies have argued that masculinity is linked to war. We conducted a web-based survey to examine relationships between gender, attitudes toward war, and masculinities within a sample of Japanese adults of both sexes (N = 366). Our results indicated that while men were more likely than women to accept war, the relationship between attitudes toward war and masculinities was inconclusive. Moreover, the results suggested that favorable attitudes toward war among men could be attenuated by interpersonal orientations. Based on our findings, we recommend a reexamination of attitudes toward war within the Japanese population.

Although various norms for reciprocity-based cooperation have been suggested that are evolutionarily stable against invasion from free riders, the process of alternation of norms and the role of diversified norms remain unclear in the evolution of cooperation. We clarify the co-evolutionary dynamics of norms and cooperation in indirect reciprocity and also identify the indispensable norms for the evolution of cooperation. Inspired by the gene knockout method, a genetic engineering technique, we developed the norm knockout method and clarified the norms necessary for the establishment of cooperation. The results of numerical investigations revealed that the majority of norms gradually transitioned to tolerant norms after defectors are eliminated by strict norms. Furthermore, no cooperation emerges when specific norms that are intolerant to defectors are knocked out.

Intuition and experimental evidence suggests that increases in prey availability lead to increases in predator populations. However, theoretical models paradoxically suggest that increased prey can lead to instability in the predator-prey ecosystem and possible extinction. To resolve this paradox, I considered social interactions between predators. Some predators produce (find their own prey) and others scrounge (join in on their companions’ prey). I showed mathematically that when scrounging is prevalent, the ecosystem becomes stable and hence, the paradox disappears. My results highlight the importance of social interactions within group-living animals in maintaining stability of ecological communities.

The present study investigated the association between a polymorphism of the serotonin 2A receptor (5-HT2AR) gene and the form of impulsive choice known as delay discounting. Using a hypothetical situation, we asked Japanese participants to choose between receiving (or paying) a different amount of money immediately or with a specified delay (one week, two weeks, one month, six months, one year, five years, or 25 years), and estimated the parameters of intertemporal choice models (exponential, hyperbolic, hyperbolic with exponent, and quasi-hyperbolic). Regardless of the genotypes, the hyperbolic with exponent model, which always indicated minimum AICc (Akaike Information Criterion with small sample correction), fitted better the observed data than the other models. Future gains were discounted more steeply than future losses. Moreover, as expected, individuals with the AA genotype of the 5-HT2AR A-1438G polymorphism discounted the future more steeply than did individuals with the GG genotype, although this effect was limited to only gains. The findings implied individual differences based on the A-1438G polymorphism in the modulation of serotonin in the reward valuation underlying delay discounting.

Although hazards are inherently uncertain, research on citizens’ judgments of risk, hazard preparedness, and support for mitigation policies has rarely accounted for citizens’ beliefs about the uncertainty of fields estimating hazard risk or in science as providing accurate, unbiased knowledge, nor citizens’ need to achieve quick, certain answers. Parallel online surveys of residents of earthquake-prone areas of Japan and the United States revealed that belief in scientific positivism increased policy support in both countries (as did need for closure among Americans), and belief in seismological uncertainty reduced judged earthquake risk in Japan, with small effect sizes. Preparedness was unaffected by these predictors. Associations of other factors (quake experience; trust in experts; demographics) with dependent variables were consistent with other studies, and Japanese-American differences were small on dependent variables and in most predictors. Motivation (i.e., high involvement with the topic, relevance of the fictional earthquake rupture forecast in a quasi-experiment embedded in the survey, and judged ability to use its information) strongly affected judged risk, preparedness and policy support. Low-motivation Japanese and high-motivation Americans exhibited associations most similar to overall findings for their nations. Implications of these findings for hazards research and risk communication are discussed.

We examined the effect of religious priming on a Japanese sample in an anonymous dictator game whereas previous studies on religious priming on prosociality had mainly been conducted within Western contexts. The current study attempted to examine whether religion increases prosocial behaviour in a Japanese sample through the replication of ‘God is Watching You’ (Shariff & Norenzayan, 2007) where it was found that participants primed with religion-related words and secular justice-related words behaved more prosocially than participants primed with neutral words in an anonymous dictator game. The current experiment was conducted with Japanese students (n = 106) to examine whether the results of the original study could be applied to Japanese people. The results showed that among the three priming conditions (control, religion, secular justice), there was no difference in the amount of money participants allocated to anonymous strangers, although in the secular justice priming condition, theists allocated more money than atheists. The results might be due to the fact that the religious priming words used in the original study did not precisely activate the propositional network of religion that Japanese participants have. More culture-specific studies are necessary to examine how religious priming works for non-Westerners.

Previous research has suggested that stability of self-concept differs across cultures: in North American cultural contexts, people’s self-concept is stable across social contexts, whereas in Japan, different self-concepts are activated within specific social contexts. We examined the implications of this cultural difference for preference-choice consistency, which is people’s tendency to make choices that are consistent with their preferences. We found that Japanese were less likely than Americans to choose items that they liked the most, showing preference-choice inconsistency. We also investigated the conditions in which Japanese might exhibit greater preference-choice consistency. Consistent with research showing that in Japanese culture, the self is primarily conceptualized and activated by social contexts, we found that subtle social cues (e.g., schematic representations of human faces) increased preference-choice consistency among Japanese, but not among Americans. These findings highlight that choices do not reveal preferences to the same extent in all cultures, and that the extent to which choices reveal preferences depends on the social context.

Mortality salience (MS) has been shown to lead to derogation of others with dissimilar worldviews, yet recent research has shown that Asian-Americans who presumably adopt an interdependent self-construal (SC) tend to reveal greater tolerance after MS induction. In the present study, we demonstrated that Japanese individuals who are high on interdependent SC indeed show greater tolerance towards worldview-threatening other in the MS (vs. control) condition, thus replicating the prior research. Extending this research, we also found that interdependent people’s tolerance towards worldview-threatening other was mediated by increased activity in the right ventrolateral prefrontal cortex (rVLPFC) in the MS condition. These data suggested that when exposed to death-related stimuli, highly interdependent individuals may spontaneously activate their neural self-control system which may serve to increase tolerance towards others.

We described associations between the type of disaster experience and change in instrumental activities of daily living among older adult survivors before-after a terrible disaster.

Methods

The study took advantage of a “natural experiment” afforded by the Japan Gerontological Evaluation Study (JAGES), a nationwide cohort study established in 2010, seven months prior to the earthquake and tsunami. A follow-up survey was conducted in 2013. This study was conducted in Iwanuma, which was directly struck by tsunami. Our sample comprised community-dwelling aged survivors in Iwanuma who responded to questions about personal circumstances and functional status both before and after the disaster (N = 3547). Personal experiences of earthquake and tsunami damage was used as an exposure variable. The outcome was changes in self-reported 13-item instrumental activities of daily living (IADL), which was assessed both before and after the disaster.

Results

Among the participants, 931 reported losing family member(s) to the disaster, while a further 549 reported losing friend(s). More than half of the participants reported any damage to their houses while approximately 1 in 8 lost their car(s). The multivariable OLS regression revealed that complete house loss and disruption of internal medicine were associated with significantly worse IADL: −0.67 points (95%CI: −0.99, −0.34) for entirely destroyed homes; −0.40 points (95% CI: −0.71, −0.092) for disruption of internal medicine. By contrast, loss of family/friends/pets/cars and disruption to the other medical service were not associated with decline in IADL.

Conclusion

Complete house loss and disruption of access to internal medicine after a disaster were associated with significant adverse impact on decline in physical and cognitive functions 2.5 years after the disaster, while loss of family/friends was not.

Introduction
There are few intervention studies that demonstrated linking social participation to lower risk of cognitive decline. We examined prospectively the protective effect of a community intervention program promoting social participation on the incidence of cognitive disability.

Methods
The baseline was established in a survey of community-dwelling older people aged 65 years old or more in July 2006 (2793 respondents, response rate 48.5%). The setting was Taketoyo town in Japan, where municipal authorities launched an intervention that was based on the establishment of community-based centers called “salons,” where the town’s senior residents could congregate and participate in social activities, ranging from arts and crafts, games, and interactive activities with preschool children. Three salons were established in May 2010, and a total of 10 salons were in operation by 2013. We recorded the frequency of salon participation among survey respondents till 2013 and conducted two follow-up surveys (in 2010 and 2013) to collect information about health status and behaviors. The onset of cognitive disability was followed from May 2007 to January 2014. We used the marginal structural models to evaluate the effect of program.

Results
The range of prevalence of cognitive disability was from 0.2% to 2.5% during the observation period. The proportion of respondents who participates to salons increased over time to about 11.7%. The frequency of salon participation was protectively associated with cognitive decline, even after adjusting for time-dependent covariates and attrition (odds ratio = 0.73, 95% confidence interval: 0.54–0.99).

Discussion
Our study suggests that operating community salons that encourage social interactions, light physical activity, and cognitive activities among older participants may be effective for preventing cognitive decline. In future studies, we need to understand what sorts of activities (e.g., those involving light physical activity vs. purely intellectual activities) are most effective in maintaining cognitive function.

Using a recently created preemptive strike game (PSG) with 176 participants, we investigated if the motivations of spite and/or fear promotes aggression that requires a small cost to the aggressor and imposes a larger cost on the opponent, and confirmed the earlier finding that fear does but spite does not promote intergroup aggression when the groups are characterized as minimal groups; additionally, the rate of intergroup aggression did not vary according to the group membership of the opponent. The PSG represents a situation in which both the motivations of spite and of fear can logically drive players to choose an option of aggression against an opponent. Participants decide whether or not to attack another participant, who also has the same capability. The decision is made in real time, using a computer. We discuss theoretical implications of our findings on the evolutionary foundations of intragroup cooperation and intergroup aggression. The evolutionary model of intergroup aggression, or the parochial altruism model, posits that intragroup cooperation and intergroup aggression have co-evolved, and thus it predicts both intragroup cooperation and intergroup aggression to emerge even in a minimal group devoid of a history of intergroup relationships. The finding that only intragroup cooperation but not intergroup aggression emerged in the minimal group experiments strongly suggests that intergroup aggression involves a psychological mechanism that is independent from that of intragroup cooperation. We further discuss the implications of these findings on real-world politics and military strategy.

In social dilemma games, human participants often show conditional cooperation (CC) behavior or its variant called moody conditional cooperation (MCC), with which they basically tend to cooperate when many other peers have previously cooperated. Recent computational studies showed that CC and MCC behavioral patterns could be explained by reinforcement learning. In the present study, we use a repeated multiplayer prisoner’s dilemma game and the repeated public goods game played by human participants to examine whether MCC is observed across different types of game and the possibility that reinforcement learning explains observed behavior. We observed MCC behavior in both games, but the MCC that we observed was different from that observed in the past experiments. In the present study, whether or not a focal participant cooperated previously affected the overall level of cooperation, instead of changing the tendency of cooperation in response to cooperation of other participants in the previous time step. We found that, across different conditions, reinforcement learning models were approximately as accurate as a MCC model in describing the experimental results. Consistent with the previous computational studies, the present results suggest that reinforcement learning may be a major proximate mechanism governing MCC behavior.

This study examines the social features of the 31 most popular games in Japan’s rapidly expanding mobile social game market, as ranked through a survey of 2660 teenagers and young adults in November 2013. Results showed that all 31 games had at least one of the three social features, namely, connections to social networking services (SNSs), competition, and cooperation. In the games, SNS connections were present in 84 % of games, competition in 87 % of games, cooperation in 94 %. Among the cooperative features, individualistic cooperative play was more prevalent than team play. Keywords：Smartphones Social features Social games Systematic analysis Mobile device.

In this article, we present evidence that in four different cultural groups that speak quite different languages (Brazil, India, Japan, and the USA) there are cases of justified true beliefs that are not judged to be cases of knowledge. We hypothesize that this intuitive judgment, which we call “the Gettier intuition,” may be a reflection of an underlying innate and universal core folk epistemology, and we highlight the philosophical significance of its universality.

Following major disasters, purchase avoidance behavior toward products that are caused by stigma often results. For example, after the Tohoku Earthquake and Fukushima Daiichi Nuclear Disaster, consumers have avoided products from Fukushima. Attempts have been made to diminish this purchase avoidance behavior, but have been found to be ineffective. The reasons for ineffectiveness of strategies within this context were empirically examined based on matching and mismatching effects of messages. In two studies (Study 1, N = 113; Study 2, N = 364), the effects of affective messages and cognitive messages were compared, and the effectiveness of affective messages was found to be consistently weaker than that of cognitive messages. Message producers often present affective messages with the expectation of observing the matching effect. However, findings suggest that these presentation strategies will fail, and that the mismatching effect should be used instead. The best method of message presentation to reduce purchase avoidance behavior in a disaster area is discussed.

The present research explored people’s everyday practice of counteractive control. Experience sampling was used to test our prediction that strong temptations would promote self-control. Participants were 237 Japanese citizens with ages ranging from 18 to 69. Results indicated that perceived temptation prompted stronger resistance and restraint of behaviors, compared to those cases where no conflict was perceived. In addition, multilevel path analysis revealed the underlying process such that (a) a strong desire toward temptation intensified perception of conflict; (b) perceived conflict bolstered the value of goals that were in disagreement with the temptation; and (c) highly valued goals promoted self-control (i.e., stronger resistance and hence less yielding to temptation).

This study examined the association between salivary oxytocin (sOT) levels and generosity in preschoolers. Fifty preschoolers played two dictator games (DG) by deciding how to allocate 10 chocolates between themselves and another child, who was either from the same class as the participant (ingroup member), or an unknown child from another class (outgroup member). sOT levels were assessed in saliva collected from the children immediately prior to the DG tasks. While sOT levels were negatively associated with allocations made to both ingroup and outgroup members by boys, among girl sOT levels were positively related to allocations made to ingroup members, and unrelated to allocations made to outgroup members. These results suggest sex differences in the association between salivary oxytocin and generosity.

A number of empirical studies have suggested that individual differences in asocial exploration tendencies in animals may be related to those in social information use. However, because the ‘exploration tendency’ in most previous studies has been measured without considering the information-gathering processes, it is yet hard to conclude that the animal asocial exploration strategies may be tied to social information use. Here, we studied human learning behaviour in both asocial and social two-armed bandit tasks. By fitting reinforcement learning models including asocial and/or social decision processes, we measured each individual’s (1) asocial exploration tendency and (2) social information use. We found consistent individual differences in the exploration tendency in the asocial tasks. We also found substantive heterogeneity in the adopted learning strategies in the social task: Nearly one-third of participants used predominantly the copy-when-uncertain strategy, while the remaining two-thirds were most likely to have relied only on asocial learning. However, we found no significant individual association between the exploration frequency in the asocial task and the use of the social information in the social task. Our results suggest that the social learning strategies may be independent from the asocial exploration strategies in humans.

Iyengar et al. (1984) discovered the media priming effect, positing that by drawing attention to certain issues while ignoring others, television news programs help define the standards by which presidents are evaluated. We conducted a direct replication of Experiment 1 by Iyengar et al. (1984), with some changes. Specifically, we (a) collected data from Japanese undergraduates; (b) reduced the number of conditions to two; (c) used news coverage of the issue of relocating US bases in Okinawa as the treatment; (d) measured issue-specific evaluations of the Japanese Prime Minister in the pretreatment questionnaire; and (e) performed statistical analyses that are more appropriate for testing heterogeneity in the treatment effect. We did not find statistically significant evidence of media priming. Overall, the results suggest that the effects of media priming may be quite sensitive either to the media environment or to differences in populations in which the effect has been examined.

No previous study has been able to examine the association by taking account of risk factors for dementia before and after the disaster. We prospectively examined whether experiences of a disaster were associated with cognitive decline in the aftermath of the 2011 Great East Japan Earthquake and Tsunami. The baseline for our natural experiment was established in a survey of older community-dwelling adults who lived 80 km west of the epicenter 7 mo before the earthquake and tsunami. Approximately 2.5 y after the disaster, the follow-up survey gathered information about personal experiences of disaster as well as incidence of dementia from 3,594 survivors (82.1% follow-up rate). Our primary outcome was dementia diagnosis ascertained by in-home assessment during the follow-up period. Among our analytic sample (n = 3,566), 38.0% reported losing relatives or friends in the disaster, and 58.9% reported property damage. Fixed-effects regression indicated that major housing damage and home destroyed were associated with cognitive decline: regression coefficient for levels of dementia symptoms = 0.12, 95% confidence interval (CI): 0.01 to 0.23 and coefficient = 0.29, 95% CI: 0.17 to 0.40, respectively. The effect size of destroyed home is comparable to the impact of incident stroke (coefficient = 0.24, 95% CI: 0.11 to 0.36). The association between housing damage and cognitive decline remained statistically significant in the instrumental variable analysis. Housing damage appears to be an important risk factor for cognitive decline among older survivors in natural disasters.

Binary or dichotomous thinking may lead to aggression throughout people’s lifespan; additionally, relationships are likely to be affected by types of aggression (i.e. physical aggression, verbal aggression, anger, and hostility) as well as gender and age. Using large-scale data (N = 2,315), the current study tested if age or gender moderated dichotomous thinking’s correlation with four different types of aggression. Participants (Mage = 36.1, SD = 16.2, range = 18–69) completed the Dichotomous Thinking Inventory and the Buss-Perry Aggression Questionnaire. Dichotomous thinking differentially affected aggression depending on participants’ age: dichotomous thinking and aggression were more strongly correlated in younger participants. Individuals’ tendency to think dichotomously appeared relatively stable; however, age appeared to moderate dichotomous thinking’s effects.

Recent developments in communication technologies have changed how people connect and interact with each other. This study investigates whether and how online communication with strong ties (mobile phone and social networking service [SNS]) enhances subjective well-being in Japan. Study 1 examined whether the correlation between happiness and mobile phone use was mediated by the number of offline and online friends. Study 2 assessed the associations between the Japanese relationship-oriented value “interdependent self-view,” life satisfaction, and the use of SNS. Results indicate that only the use of LINE (an instant messaging application), which is the most popular SNS in Japan, was significantly correlated with life satisfaction and interdependent self-view. The number of friends (offline and online) mediated the effect of LINE use on life satisfaction. Interdependent self-view was significantly correlated with the frequency of LINE use, homogeneity of LINE friends, and life satisfaction. These results indicate that the use of a dominant online communication method with strong ties is significantly correlated with subjective well-being, and this significant correlation is mediated by the number of offline and online friends.

Although a request for help can impose a burden on the provider and has the potential of harming a relationship, the theory of amae suggests that in fact it could help promote a stronger relationship. In an experiment, both Japanese and American participants who were asked for help from a confederate increased their liking of the confederate relative to the baseline. Sociable impression of the confederate and perceived closeness of the relationship also increased relative to the baseline. There was, however, no such increase when participants helped the confederate without receiving a direct request. This study suggests that despite the potential risks to relationships, asking favors can provide opportunities for requesters to build and promote relationships.

This paper examined temporal changes in self-esteem among middle school students in Japan from 1989 to 2002. Previous research showed that self-esteem decreased among middle school students between 1999 and 2006. However, it was unclear whether such a decrease was also present in other periods of time. To obtain a better understanding of how people adapt to socio-economic environments, it is important to gain a more comprehensive view of such long-term cultural/social changes. Therefore, to supplement the findings of the existing research on changes in self-esteem, we analyzed large-sample time-series data collected in Japan in 1989 and 2002. We found that middle schoolers’ self-esteem decreased from 1989 to 2002, consistent with previous research. Thus, our study extends the previous research by presenting additional data showing the decrease in self-esteem in Japan.

Ontogenic studies of human prosociality generally agree on that human prosociality increases from early childhood through early adulthood; however, it has not been established if prosociality increases beyond early adulthood. We examined a sample of 408 non-student residents from Tokyo, Japan, who were evenly distributed across age (20–59) and sex. Participants played five economic games each separated by a few months. We demonstrated that prosocial behavior increased with age beyond early adulthood and this effect was shown across all five economic games. A similar, but weaker, age-related trend was found in one of three social value orientation measures of prosocial preferences. We measured participants’ belief that manipulating others is a wise strategy for social success, and found that this belief declined with age. Participants’ satisfaction with the unilateral exploitation outcome of the prisoner’s dilemma games also declined with age. These two factors—satisfaction with the DC outcome in the prisoner’s dilemma games and belief in manipulation—mediated the age effect on both attitudinal and behavioral prosociality. Participants’ age-related socio-demographic traits such as marriage, having children, and owning a house weakly mediated the age effect on prosociality through their relationships with satisfaction with the DC outcome and belief in manipulation.

Despite the repeatedly raised criticism that findings in economic games are specific to situations involving trivial incentives, most studies that have examined the stake-size effect have failed to find a strong effect. Using three prisoner’s dilemma experiments, involving 479 non-student residents of suburban Tokyo and 162 students, we show here that stake size strongly affects a player’s cooperation choices in prisoner’s dilemma games when stake size is manipulated within each individual such that each player faces different stake sizes. Participants cooperated at a higher rate when stakes were lower than when they were higher, regardless of the absolute stake size. These findings suggest that participants were ‘moral bargain hunters’ who purchased moral righteousness at a low price when they were provided with a ‘price list’ of prosocial behaviours. In addition, the moral bargain hunters who cooperated at a lower stake but not at a higher stake did not cooperate in a single-stake one-shot game.